People with autosomal dominant polycystic kidney disease (ADPKD) are at a high risk of developing kidney failure during their lives. Although there are many strategies that can be used to help reduce this risk, Jynarque is the only medicine approved for this purpose.
How Does Jynarque Work for People With ADPKD?
Autosomal dominant polycystic kidney disease (ADPKD) is a kidney condition that is passed down from parents to their children. This condition causes fluid-filled sacs (or cysts) to form on the kidneys. Over time, as more of these cysts form, the kidneys begin to change shape, growing much larger and eventually losing their ability to function correctly.
People with this condition usually do not develop symptoms until adulthood and are most often diagnosed between the ages of 30 to 50. One of the most common symptoms of ADPKD is high blood pressure. Many people with this condition also experience pain near the kidneys due to various causes, including infections in the kidneys and urinary tract, bursting cysts, and kidney stones.
Everyone with ADPKD will eventually develop chronic kidney disease (CKD), a progressive condition that worsens with time. CKD happens in the following stages:
- Stages 1 or 2: These are the early stages of CKD, when the kidneys are still working well enough that people typically don’t have symptoms.
- Stages 3 or 4: These are the later stages of CKD, when kidney function drops below what is needed to properly filter the blood, causing symptoms.
- Stage 5: This is the final stage of CKD, also known as kidney failure, when the kidneys stop working completely. If a person does not get dialysis or does not receive a transplant, this stage can be life-threatening.
The key to treating ADPKD is to slow down any damage to the kidneys. One way to do this is to treat high blood pressure, since high blood pressure places more strain on the kidneys. Another way to do this is to slow down the growth of cysts by drinking plenty of fluids throughout the day and avoiding caffeine. Your health care provider may recommend other lifestyle changes as well, such as exercising, limiting your salt intake, and quitting smoking.
Jynarque works in a unique way to help slow down the growth of cysts that damage the kidneys. The active ingredient, tolvaptan, blocks a substance in the body called vasopressin from binding to the vasopressin V2-receptor in the kidneys. In people with ADPKD, this slows down the creation of new cysts and the growth of old cysts, helping the kidneys to maintain their function for longer.
Is There Any Reason I Shouldn’t Use This Medicine?
Jynarque may not be a safe option for everyone. It is important that you tell your health care provider about any past or current medical conditions, including liver problems or high or low sodium levels.
This medicine can increase the amount of urine you make, so it is important to let your health care provider know if you have trouble peeing. This could be due to a kidney stone or a past injury that is causing a blockage in your urinary tract. You should also let them know if you have any conditions that prevent you from being able to sense when you are thirsty or to drink fluids throughout the day.
How Do I Use It?
Jynarque is a tablet taken by mouth twice every day, with or without food. The first dose of the day should be taken right after you wake up in the morning. The second dose of the day should be taken 8 hours after the first dose. For example, if you wake up at 8 in the morning, you will take a dose at 8 in the morning and another dose at 4 in the afternoon. Your morning dose will always be larger than your afternoon dose. Make sure that you are taking the right dose for the time of day.
When you first start taking Jynarque, you will start with a lower daily dose. If you do not have any issues with the medicine during the first 1-2 weeks, your health care provider may tell you to increase your dose. If you do not have any issues after increasing the dose, your health care provider may tell you to increase your dose one more time.
Once you have started this medicine, your health care provider will monitor your liver function on a regular basis. It is important that you keep all of your appointments to have your blood levels checked. Depending on your levels, you may need to decrease your dose, stop taking the medicine for a few days, or stop taking it completely.
If you miss a dose of this medicine, do not take the missed dose. Instead, wait until your next dose is due. It is important that you stay on the set schedule of taking one dose when you wake up and another dose 8 hours later. Some people may find it helpful to set an alarm as a reminder to take their second dose at the right time.
How Was It Studied?
Two studies were done to see if Jynarque is safe and effective for adults with ADPKD. About half of the people in the studies were male and half were female. Most (88%) were White, about 8% were Asian, and about 2% were Black. The race of the other people in these studies was not reported.
One study included people with ADPKD who still had mostly normal kidney function. The purpose of this study was to evaluate whether Jynarque was beneficial in people who were still in the earlier stages of CKD (stages 1 or 2). Here is some other important information about this study:
- Everyone was between the ages of 18-50, with an average age of 39.
- About four-fifths (79%) of the people in this study had high blood pressure.
- Everyone received either Jynarque or placebo, and no one knew whether they were receiving the medicine or the placebo.
- This study measured effectiveness by looking at the change in kidney size (volume) over time. This is a way of monitoring the growth of kidney cysts, which increase the size of the kidney. The study also looked at changes in kidney function, blood pressure, and pain over time.
The other study included people with ADPKD and reduced kidney function. The purpose of this study was to evaluate whether Jynarque was beneficial in people who were mostly in the later stages of CKD (stages 3 or 4). Here is some other important information about this study:
- Everyone in this study was between the ages of 18-65, with an average age of 47.
- Almost everyone (93%) had high blood pressure. About one-third (30%) of people were in stage 3a, about half (45%) were in stage 3b, and about one-fifth (19%) were in stage 4.
- At the start of the study, everyone took a placebo for one week. Then, everyone took Jynarque for 5 weeks. After this, the study was split into two groups. One group kept taking Jynarque and the other group switched back to placebo. No one knew whether they were taking the medicine or placebo.
- This study measured efficacy by looking at the change in kidney function over time.
What Were the Benefits Seen in These Studies?
People in CKD stages 1 or 2. People who took Jynarque had their kidney size increase by a smaller amount than the people who took placebo. Kidney size increased by an average of 2.8% every year in the people who took Jynarque and by an average of 5.5% every year in the people who took placebo. This means that over the 3 years of the study, the people who took Jynarque had their kidney size increase by about half as much (49%) as the people who took placebo.
The people who took Jynarque also had smaller changes in kidney function over time and were less likely to experience kidney pain than the people who took placebo. There was no difference in blood pressure between the people who took Jynarque and placebo.
People in CKD stages 3 or 4. During 1 year in this study, the people who took Jynarque had their kidney function decline at a slightly slower rate than the people who took placebo. This means that Jynarque may help some people with stage 3 or 4 CKD maintain more kidney function for a longer time.
How Quickly Will Jynarque Work for ADPKD?
Even if Jynarque is working, you may not be able to tell. Over time, it may slow down the number of cysts that form on the kidneys, which can help the kidneys to function normally for a longer time. The greatest effects may happen during the first year. But as you keep taking the medicine, your risk should continue to decrease from where it would be if you were not taking the medicine.
Since Jynarque works by slowing down the effects of ADPKD on the kidneys, it is important to keep taking it even if you can’t tell that it is working. It is also important not to stop taking any of your other kidney or blood pressure medicines. If you are concerned about any of your medicines and whether they are working for you, speak with your health care provider before making any changes.
How Can I Prevent or Manage Side Effects?
Jynarque will increase the amount of urine you produce. This may increase how often you feel the need to pee during the day and at night. Although you may not be able to stop nighttime urges completely, make sure to take Jynarque at the scheduled times in the morning and the afternoon. Taking it later in the day may increase your nighttime trips to the bathroom.
It is important to keep up with your body’s fluid needs while you are taking Jynarque so that you do not become dehydrated. To do this, you should drink water or other fluids regularly throughout the day to prevent feeling thirsty. If you do feel thirsty, be sure to drink fluids right away to quench your thirst. People who become dehydrated might develop high sodium levels in their blood. Let your health care provider know right away if you develop any symptoms of dehydration or high sodium levels, such as dizziness, weakness, unusual tiredness, confusion, or an abnormal heart rhythm.
These are not all of the possible side effects. Talk with your health care provider if you are having symptoms that bother you. If you experience anything that you think may be caused by Jynarque, you can also report side effects to the FDA at 800-FDA-1088.
Are There Any Interactions With Other Medicines?
Jynarque can block the effects of another medicine called desmopressin (DDAVP). This medicine is typically used to treat a condition called diabetes insipidus.
There are many medicines that can alter the blood levels of Jynarque. Some of these medicines may increase the side effects from Jynarque while others may reduce the effects of Jynarque. In certain cases, these effects are so significant that these medicines should not be taken together.
Make sure your health care provider or pharmacist is aware of all the prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, or other supplements you take or have recently taken. This will help them to determine the best treatment plan for you.
Are There Any Interactions With Foods or Drinks?
Do not eat grapefruit or drink grapefruit juice while you are using Jynarque. Grapefruit increases the levels of Jynarque in the body, which can increase the risk of side effects. This interaction will happen even if grapefruit is consumed at a different time of day than the medicine, so it is important to avoid grapefruit completely.
Are There Any Special Steps Required to Get This Medicine?
Since Jynarque has the potential to cause liver damage in rare cases, it is only available through a restricted program called the Jynarque REMS Program. Before you can start the medicine, you must enroll in this program and have a blood test to check your liver function. Once you’ve started taking the medicine, you will have your liver function checked regularly. It is important that you keep all of your scheduled appointments for blood work so that you are able to continue taking Jynarque.
As part of the restricted program, Jynarque is only available from specific pharmacies. Your health care provider will send your prescription to one of these pharmacies, which will ship the medicine directly to you once all requirements have been met.
Is There a Coupon Card Available?
There is a savings coupon available from the manufacturer that may allow you to pay as little as $10 for your prescription. Whether you are eligible depends on whether you have prescription insurance and what type of insurance you have. You can find out more at www.jynarque.com/copay-assistance.